The present invention relates generally to a formwork or shuttering assembly for the encased concrete construction system.
One known form of such an assembly is made up of side walls and optionally end walls, to be disposed at the appropriate locations, wherein the walls are provided at their edges with grooves and projections which are capable of interengaging for securing the walls in position relative to each other, with the side walls being connected together by bars or tie members. The walls comprise for example a hard plastic foam material. A largescale assembly of that nature, as disclosed for example in German published specification (DE-AS) No. 26 18 215, may be used in many situations and permit buildings to be erected quickly and at low cost, while also providing good external and internal thermal insulation, with the side walls thus acting as a form of cladding.
However, various disadvantages are often found with the known forms of such assemblies, more particularly having regard to the wide range of requirements which are to be made in respect thereof. For example, where the connecting bars or tie members comprise for example a hard foam, being produced in one piece with the side walls for example, there is the possibility of fire striking through the wall along the tie members. On the other hand, in such an assembly as disclosed for example in U.S. Pat. No. 4,223,501, the tie members are in the form of metal grid or lattice members or sheet metal members which are fitted into the mould during manufacture of the assembly. That is a difficult and complicated operation, while also giving rise to what are known as cold bridges through the wall, because the metal members, in order to provide a secure anchoring action, terminate comparatively close to the outside surface of the wall built with the assemblies. In an assembly as disclosed in U.S. Pat. No. 3,788,020, the tie members are in the form of sheet metal members which are subsequently fitted into pre-formed slots or grooves in the side walls of the assembly, which results in the side walls being considerably weakened due to the provision of the slots or grooves, while also permitting the formation of cold bridges.
There are therefore a number of aspects in which improvement in the above-discussed assemblies would be desirable, while nonetheless the assemblies remain strong and stable, having regard to the concrete filling which is introduced thereinto and which may frequently extend over the height of a complete story, as well as being capable of resisting internal and external loadings applied thereto and providing inexpensive manufacture and easy transportation by virtue of not taking up a great deal of space.